Polyolefin dispersants and methods of making and using thereof

ABSTRACT

Provided herein are polyolefin dispersants, as well as methods for producing polyolefin dispersants. The polyolefin dispersants can be defined by the formula below 
                         
where R x  is cationic initiator residue; R a  is a polyolefin group; R 1  and R 2  are each, independently in each —(CR 1 R 2 ) unit, H, alkyl, alkoxy, or alkylaryl; R 3  and R 4  are each, independently, H, alkyl, or alkoxy; m is an integer from 1 to 20; n is an integer from 1 to 6; r is an integer from 1 to 4; Y is a polyvalent amine linker comprising one or more tertiary amines, wherein the polyvalent amine linker does not include a primary amine or a secondary amine; and A is absent, or comprises a dispersive moiety.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application claims the benefit of U.S. Provisional Application No.62/560,036, filed Sep. 18, 2017, which is hereby incorporated herein byreference in its entirety.

BACKGROUND

Lubricating motor oils intended for use in internal combustion enginesare typically formulated with a variety of additives that are intendedto aid in the reduction of corrosion, deposit formation, wear, etc.Ashless dispersants are a type of additive. The role of dispersants inlubricating oils is to regulate viscosity increases and prevent theformation of sludge, varnish, and other deposits, which occur due to theformation and presence of soot and other carbonaceous impurities thatoriginate from the incomplete oxidation of fuel and that enter the baseoil from the combustion chamber under normal operation of the engine. Inaddition, high molecular weight dispersants may also reduce or preventparticle-induce wear.

Ideally, dispersants should also be compatible with (i.e., benigntoward) engine components that come into contact with the lubricatingoil, including metal surfaces, gaskets, and seals. However, manyexisting dispersants can damage engine components, leading to equipmentfailure. Dispersants that exhibit improved compatibility with enginecomponents, including gaskets and seals, can be used to formulatelubricating motor oils with enhanced performance characteristics.

SUMMARY

Polyolefin dispersants that include one or more tertiary amines but lackprimary and secondary amines are described herein. Because thepolyolefin dispersants include one or more tertiary amines and noprimary amines or secondary amines, the dispersants can exhibitincreased compatibility towards fluoroelastomeric automotive seals.

For example, provided herein are polyolefin dispersants defined byFormula I below

where R^(x) is a cationic initiator residue; R^(a) is a polyolefingroup; R¹ and R² are each, independently in each —(CR¹R²) unit, H,alkyl, alkoxy, or alkylaryl; R³ and R⁴ are each, independently, H,alkyl, or alkoxy; m is an integer from 1 to 20; n is an integer from 1to 6; r is an integer from 1 to 4; Y is a polyvalent amine linkercomprising one or more tertiary amines, wherein the polyvalent aminelinker does not include a primary amine or a secondary amine; and A isabsent, or comprises a dispersive moiety.

Also provided are methods of making the polyolefin dispersants describedherein. The polyolefin dispersants can be formed via post-polymerizationmodification of polyolefins. For example, the polyolefin dispersants canbe derived from polyolefin substrates bearing a leaving group (e.g., ahalogen) that is readily displaceable by nucleophilic compounds withoutcompeting elimination. Suitable primary halogen-terminated polyolefinscan be prepared, for example, via in situ chain end functionalization ofliving carbocationic polyolefins by direct addition of alkoxybenzenederivatives to a living polymerization, or alternatively, to apre-formed tert-chloride-terminated polyolefin activated by a Lewisacid, or alternatively to an olefin-terminated polyolefin activated by aprotic/Lewis acid combination.

In some embodiments, methods for preparing polyolefin dispersants cancomprise (a) generating a quasiliving polyolefin in a reversibledeactivation-type living polymerization; (b) adding to the reversibledeactivation-type living polymerization of step (a) a quenching agentdefined by Formula V to generate a phenoxy-quenched precursor;

wherein R¹, R², R³, R⁴, and m are as defined above with respect toFormula I, and X is a leaving group; (c) reacting the phenoxy-quenchedprecursor with a polyamine to form a polyamine-capped precursor; and (d)reacting the polyamine-capped precursor with an anhydride to form thepolyolefin dispersant.

DESCRIPTION OF DRAWINGS

FIG. 1A is a ¹H NMR (600 MHz, CD₃Cl, 22° C.) spectrum ofα,ω-bis[4-(3-bromopropoxy)phenyl]polyisobutylene obtained by directquenching of a TiCl₄-catalyzed quasiliving isobutylene polymerization.

FIG. 1B is a ¹H NMR (600 MHz, CD₃Cl, 22° C.) spectrum ofpolyisobutylene-piperazinylethylamine obtained by reaction of PIB-Brwith MIBK-protected 1-(2-aminoethyl)piperazine and displacement of theMIBK protecting group by hydrolysis FIG. 2 is a homonuclear correlationspectroscopy (COSY) NMR (600 MHz, CD₃Cl, 22° C.) spectrum ofpolyisobutylene-piperazinylethylamine demonstrating cross-peakcorrelation that was used to identify peaks h, k, and 1.

FIG. 3 is a ¹³C NMR (600 MHz, CD₃Cl, 22° C.) spectrum ofpolyisobutylene-piperazinylethylamine obtained by reaction of PIB-Brwith MIBK-protected 1-(2-aminoethyl)piperazine and displacement of theMIBK protecting group by hydrolysis.

FIG. 4 compares the ¹H NMR (300 MHz, CD₂Cl₂, 22° C.) spectra ofpolyisobutylene-piperazinylethylamine-glutarimide (PIB-PzEA-Glutarimide)(top trace), polyisobutylene-piperazinylethylamine-phthalimide(PIB-PzEA-Phthalimide) (middle trace) and polyisobutylene-piperazinylethylamine-naphthalimide (PIB-PzEA-Naphthalimide)(bottom trace) obtained by reaction of primary amine-terminated PIB-PzEAwith respective anhydrides.

FIG. 5 is the ¹H NMR (300 MHz, CD₂Cl₂, 22° C.) spectrum ofpolyisobutylene-piperazinylethylamine-pyromellitimide(PIB-PzEA-Pyromellitimide) obtained by reaction of two equivalents ofPIB-PzEA with one equivalents of pyromellitic dianhydride.

FIG. 6 is the GPC trace of polyisobutylene-piperazinylethylamine-pyromellitimide(PIB-PzEA-Pyromellitimide) obtained by reaction of two equivalents ofPIB-PzEA with one equivalents of pyromellitic dianhydride.

FIG. 7 is the ¹H NMR spectrum (300 MHz, CD₂Cl₂, 22° C.) ofpolyisobutylene-bis(2-phthalimidoethyl)amine (PIB-DETA-Phthalimide)obtained by reaction of one equivalents of PIB-DETA with at least twoequivalents of phthalic anhydride.

FIG. 8A is a MALDI-TOF mass spectrum ofpolyisobutylene-piperazinylethylamine (PIB-PzEA) prepared by the drieddroplet method using DCTB as the matrix, AgTFA as the cationizing agent,and THF as the solvent.

FIG. 8B is a MALDI-TOF mass spectrum ofpolyisobutylene-piperazinylethylamine-phthalimide (PIB-PzEA-Phthalimide)prepared by the dried droplet method using DCTB as the matrix, AgTFA asthe cationizing agent, and THF as the solvent.

FIG. 9 is a plot of mass-to-charge ratio (M/z), measured at the maximumof each peak of the major distribution, versus degree of polymerization(X_(n)) for PIB-PzEA, PIB-PzEA-Phthalimide, PIB-PzEA-Naphthalimide,PIB-PzEA-Pyromellitimide, PIB-PzEA-Glutarimide, PIB-DETA andPIB-DETA-Phthalimide. Best fit lines were obtained using linearregression analysis.

FIG. 10 is a plot of the TGA curves for PIB-PzEA, PIB-PzEA-Phthalimide,PIB-PzEA-Naphthalimide, PIB-PzEA-Pyromellitimide, PIB-PzEA-Glutarimide,PIB-DETA, PIB-DETA-Phthalimide andPoly(styrene-alt-(PIB-PzEA-Maleimide)).

FIGS. 11A and 11B show Langmuir adsorption isotherms forPIB-PzEA-Glutarimide, PIB-PzEA-Phthalimide, PIB-PzEA-Naphthalimide, andPIB-PzEA-Pyromellitimide, plotted on a mass basis (FIG. 11A) and a molarbasis (FIG. 11B). The methods used to construct the plots in FIGS. 11Aand 11B are described in Ho, Y.-S., et al. Regression Analysis for theSorption Isotherms of Basic Dyes on Sugarcane Dust. Bioresour. Technol.2005, 96 (11), 1285-1291, which is hereby incorporated by reference inits entirety.

FIGS. 12A and 12B show linearized Langmuir isotherms forPIB-PzEA-Glutarimide, PIB-PzEA-Phthalimide, PIB-PzEA-Naphthalimide andPIB-PzEA-Pyromellitimide, plotted on a mass basis according to Equation1 (FIG. 12A) and a molar basis according to Equation 2 (FIG. 12B). Themethods used to construct the plots in FIGS. 12A and 12B are found inthe following reference: Ho, Y.-S.; Chiu, W.-T.; Wang, C.-C. RegressionAnalysis for the Sorption Isotherms of Basic Dyes on Sugarcane Dust.Bioresour. Technol. 2005, 96 (11), 1285-1291, which is herebyincorporated by reference in its entirety.

DETAILED DESCRIPTION Definitions

To facilitate understanding of the disclosure set forth herein, a numberof terms are defined below. Unless defined otherwise, all technical andscientific terms used herein generally have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this disclosurebelongs. The organic moieties mentioned when defining variable positionswithin the general formulae described herein (e.g., the term “halogen”)are collective terms for the individual substituents (e.g., fluorine,chlorine, bromine, iodine, etc.) encompassed by the organic moiety. Theprefix C_(n)-C_(m) preceding a group or moiety indicates, in each case,the possible number of carbon atoms in the group or moiety that follows.

As used herein, the term “alkyl” refers to saturated, straight-chainedor branched hydrocarbon moieties. Unless otherwise specified, C₁-C₈(e.g., C₁-C₆, or C₁-C₄) alkyl groups are intended. Examples of alkylgroups include methyl, ethyl, propyl, 1-methylethyl, butyl,1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl,1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl,1-ethylpropyl, hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl,1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl,1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl,2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl,2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl,1-ethyl-1-methylpropyl, and 1-ethyl-2-methylpropyl. Alkyl substituentsmay be unsubstituted or substituted with one or more chemical moieties.The alkyl group may be substituted with one or more groups including,but not limited to, hydroxyl, halogen, acyl, alkyl, alkoxy, alkenyl,alkynyl, aryl, heteroaryl, acyl, aldehyde, amino, carboxylic acid,ester, ether, ketone, nitro, silyl, sulfo-oxo, sulfonyl, sulfone,sulfoxide, or thiol, as described below, provided that the substituentsare sterically compatible and the rules of chemical bonding and strainenergy are satisfied.

Throughout the specification “alkyl” is generally used to refer to bothunsubstituted alkyl groups and substituted alkyl groups; however,substituted alkyl groups can also specifically be referred to herein byidentifying the specific substituent(s) on the alkyl group.

For example, the term “alkylaryl” can be used to specifically refer toan alkyl group that is substituted with one or more aryl groups (e.g.,phenyl groups). When “alkyl” is used in one instance and a specific termsuch as “alkylaryl” is used in another, it is not meant to imply thatthe term “alkyl” does not also refer to specific terms such as“alkylaryl” and the like.

As used herein, the term “alkoxy” refers to a group of the formulaZ¹—O—, where Z¹ is unsubstituted or substituted alkyl as defined above.Unless otherwise specified, alkoxy groups wherein Z¹ is a C₁-C₈ (e.g.,C₁-C₆, C₁-C₄) alkyl group are intended. Examples include methoxy,ethoxy, propoxy, 1-methylethoxy, butoxy, 1-methylpropoxy,2-methylpropoxy, 1,1-dimethylethoxy, pentoxy, 1-methylbutyloxy,2-methylbutoxy, 3-methylbutoxy, 2,2-dimethylpropoxy, 1-ethylpropoxy,hexoxy, 1,1-dimethylpropoxy, 1,2-dimethylpropoxy, 1-methylpentoxy,2-methylpentoxy, 3-methylpentoxy, 4-methylpenoxy, 1,1-dimethylbutoxy,1,2-dimethylbutoxy, 1,3-dimethylbutoxy, 2,2-dimethylbutoxy,2,3-dimethylbutoxy, 3,3-dimethylbutoxy, 1-ethylbutoxy, 2-ethylbutoxy,1,1,2-trimethylpropoxy, 1,2,2-trimethylpropoxy, 1-ethyl-1-methylpropoxy,and 1-ethyl-2-methylpropoxy.

As used herein, the term “aryl” refers to groups that include amonovalent aromatic carbocyclic group of from 3 to 20 carbon atoms. Arylgroups can include a single ring or multiple condensed rings. In someembodiments, aryl groups include C₆-C₁₀ aryl groups.

Examples of aryl groups include, but are not limited to, phenyl,biphenyl, naphthyl, tetrahydronaphthyl, phenylcyclopropyl, and indanyl.In some embodiments, the aryl group can be a phenyl, indanyl or naphthylgroup. Aryl substituents may be unsubstituted or substituted with one ormore chemical moieties. Examples of suitable substituents include, forexample, alkyl, halogenated alkyl, alkoxy, alkenyl, alkynyl, aryl,heteroaryl, acyl, aldehyde, amino, carboxylic acid, cycloalkyl, ester,ether, halide, hydroxyl, keto, nitro, silyl, sulfo-oxo, sulfonyl,sulfone, sulfoxide, or thiol.

As used herein, the term “cycloalkyl” refers to a non-aromaticcarbon-based ring composed of at least three carbon atoms. Examples ofcycloalkyl groups include, but are not limited to, cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, etc. The term “heterocycloalkyl” isa cycloalkyl group as defined above where at least one of the carbonatoms of the ring is replaced by a heteroatom such as, but not limitedto, nitrogen, oxygen, sulfur, or phosphorus.

The cycloalkyl group and heterocycloalkyl group can be substituted orunsubstituted. The cycloalkyl group and heterocycloalkyl group can besubstituted with one or more groups including, but not limited to,alkyl, alkoxyl, alkenyl, alkynyl, aryl, heteroaryl, acyl, aldehyde,amino, carboxylic acid, ester, ether, halide, hydroxy, keto, nitro,silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, or thiol.

As used herein, the term “imide” refers to a chemical moiety thatincludes two acyl groups bound to nitrogen, as shown in the generalformula below.

Imide moieties can be linear or cyclic. In the case of cyclic imides, Z²and Z³, together with the atoms to which they are attached, form a five,six, seven, or eight membered ring. This ring may be unsubstituted orsubstituted with one or more chemical moieties. Examples of suitablesubstituents include, for example, alkyl, halogenated alkyl, alkoxy,alkenyl, alkynyl, aryl, heteroaryl, acyl, aldehyde, amino, carboxylicacid, cycloalkyl, ester, ether, halide, hydroxyl, keto, nitro, silyl,sulfo-oxo, sulfonyl, sulfone, sulfoxide, or thiol. This ring may also beannulated with one or more cycloalkyl, aryl, or heteroaryl rings, suchthat Z² and Z³, together with the atoms to which they are attached, forma five, six, seven, or eight membered ring that is fused to one or moreadditional cyclic moieties.

As used herein, the term “initiator” refers to a compound capable ofproviding one or more carbocations, in one embodiment, one, two, orthree carbocations, to which a monomer (e.g., olefin or isobutylene) ora comonomer may add during a carbocationic polymerization.

As used herein, the term “mono-functional initiator” refers to aninitiator that provides approximately one stoichiometric equivalent ofcarbocation relative to initiator. When a mono-functional initiator isused, the chain-end concentration is approximately equal to theinitiator concentration.

As used herein, the term “multi-functional initiator” refers to aninitiator that provides approximately x stoichiometric equivalents ofcarbocation relative to initiator, wherein x represents thefunctionality of the initiator. When a multi-functional initiator isused and the functionality of the initiator equals x, then the chain-endconcentration equals x times the initiator concentration. In someembodiments, x is 2, and the initiator is a bi-functional initiator.

As used herein, the term “initiator residue” refers to a monovalent,divalent, or polyvalent moiety that is bonded to one, two, or morepolymer groups. In certain embodiments, the initiator residue is derivedfrom an initiator. In certain embodiments, the initiator residue is theportion of an initiator that remains after forming one, two, or morecarbocations and reacting with a monomer or comonomer during apolymerization.

As used herein, the term “monomer” refers to a compound that is capableof forming one of the two or more repetitive units of a polymer. Incertain embodiments, the monomer is an olefin. In certain embodiments,the monomer is isobutene.

As used herein, the terms “polyolefin” and “polyolefin group” refer to apolymer or oligomer that comprises two or more monomeric units derivedfrom an olefin. In certain embodiments, the polyolefin is polyethylene,polypropylene, polyisobutylene, or polystyrene.

In certain embodiments, the polyolefin is a homopolyolefin. In certainembodiments, the polyolefin is a polyolefin copolymer. In someembodiments, the polyolefin has a molecular weight from about 300 to inexcess of a million g/mol. In some embodiments, the polyolefin has amolecular weight of from about 200 to 10,000 g/mol. In some embodiments,the polyolefin has a molecular weight of from about 1,000 to 5,000g/mol. In some embodiments, the polyolefin has a molecular weight offrom about 2,000 to 3,000 g/mol. In some embodiments, the polyolefin hasa molecular weight of from about 100,000 to 1,000,000 g/mol.

In some embodiments, the polyolefin has a molecular weight greater than200 g/mol. In some embodiments, the polyolefin has a molecular weightgreater than 400 g/mol. In some embodiments, the polyolefin has amolecular weight greater than 600 g/mol. In some embodiments, thepolyolefin has a molecular weight greater than 800 g/mol. In someembodiments, the polyolefin has a molecular weight greater than 1,000g/mol. In some embodiments, the polyolefin has a molecular weightgreater than 5,000 g/mol. In some embodiments, the polyolefin has amolecular weight greater than 10,000 g/mol. In some embodiments, thepolyolefin has a molecular weight greater than 100,000 g/mol. In someembodiments, the polyolefin has a molecular weight greater than 500,000g/mol. In some embodiments, the polyolefin has a molecular weightgreater than 1,000,000 g/mol. In some embodiments, the polyolefin isderived from a mono-functional initiator, bi-functional initiator, ormulti-functional initiator. In some embodiments, the polyolefin ispolyisobutene.

As used herein, the terms “polyisobutylene,” “polyisobutylene group,”and “PIB” refer to a polymer comprising two or more monomericisobutylene units. In certain embodiments, the polyisobutylene comprisesan initiator residue. In certain embodiments, the polyisobutylene is ahomopolyisobutylene. In certain embodiments, the polyisobutylene is apolyisobutylene copolymer.

As used herein, the term “quasiliving polyolefin” refers to a polyolefinthat has been formed using a reversible deactivation-type livingpolymerization. In some embodiments, the quasiliving polyolefin can be aquasiliving carbocationic polyolefin.

As used herein, the term “reversible deactivation-type livingpolymerization” refers to a polymerization process that proceeds withminimal irreversible chain termination and minimal chain transfer. Suchpolymerizations proceed by initiation followed by propagation, whereinpropagating (active) species are in equilibrium with non-propagating(dormant) polymer chains. In some embodiments, the reversibledeactivation-type living polymerization can be a reversibledeactivation-type living carbocationic polymerization, also referred toas a quasiliving carbocationic polymerization.

As used herein, the term “terminator” refers to a compound thatdeactivates a Lewis acid.

As used herein, the term “Lewis acid” refers to a chemical entity thatis capable of accepting a pair of electrons.

As used herein, the term “leaving group” refers to a functional groupthat is capable of being substituted under certain reaction conditions.Suitable leaving groups are well known in the field of organicchemistry, and include, for example, halides such as —Cl, —Br, and —I,sulfonates such as p-toluenesulfonate (tosyl), methanesulfonate (mesyl),and trifluoromethanesulfonate (triflate), as well as pseudohalides. Theterm “pseudohalide” is well known in the chemical field and is employedherein in its conventional sense to mean a substituent that exhibitssignificant similarity to the halogens as regards to their properties asa leaving group. Examples of pseudohalides include azide, nitrile(cyanide), cyanate, and thiocyanate.

Dispersants

The majority of existing motor oil dispersants are of either the Mannichtype, created by reaction of an alkylated phenol with formaldehyde and apolyamine, or the alkyl succinimide type, created by reaction of apolyamine with an alkyl succinic anhydride.

Polyisobutylene succinimide (PIBSI) dispersants represent an importantclass of alkyl succinimide type dispersants. Presently, PIBSIdispersants are prepared from polyisobutylenes (PIBs) bearing olefinicend groups. Briefly, PIB chains with olefinic end groups can besynthesized via acid-catalyzed (e.g., AlCl₃, BF₃, or BF₃ complexes)polymerization of isobutylene. BF₃-based catalysts yield high-reactivity(HR) PIBs that possess high fractions of methyl vinylidene (exo-olefin)end groups and are favored because of their higher reactivity insubsequent functionalization reactions. AlCl₃-based catalysts yield acomplex mixture of terminal olefin types, including high fractions oflow reactivity tri- and tetrasubstituted olefins.

The formation of polyisobutylene succinic anhydride (PIBSA) can then beaccomplished by reaction of olefin-terminated PIB with maleic anhydride,either through a chlorine-mediated reaction that proceeds via aDiels-Alder mechanism (PIB derived from AlCl₃ catalyst) or athermal-mediated reaction at temperatures greater than 200° C. thatproceeds through an ene mechanism (BF₃ catalyst). Subsequent imidizationof PIBSA with a heavy polyamine (e.g., triethylene tetramine, ortetraethylene pentamine) can then be carried out with the removal ofwater to form the PIBSI dispersant. The resulting PIBSI dispersantscontain numerous primary and/or secondary amines which, as discussedbelow, is a significant drawback to this class of dispersants.

In many cases, the seals found within automotive engines are formed fromfluoroelastomers (e.g., VITON®), with the main constituent of thosefluoroelastomers being repeat units derived from vinylidene difluoride.There are numerous modes of failure for automotive seals that can leadto loss of lubricant and equipment failure including shrinkage, loss ofelongation, and increased rigidity. The onset of these failures isprimarily due to degradative reactions between fluoroelastomers andlubricant additives. Due to the nature of their polar head group, PIBSIdispersants can diffuse into fluoroelastomer seals, and degrade theseals by removal of plasticizer and/or participation indehydrofluorination reactions along the fluoroelastomer backbone.Dehydrofluorination reactions introduce unsaturations along thefluoroelastomer backbone. These unsaturations can participate insubsequent crosslinking reactions or thermal oxidation, either of whichcan lead to a loss of elongation and eventual embrittlement of the seal.

Basic amines (1°, 2°, and 3°) present in existing PIBSI dispersants areresponsible for dehydrofluorination and resulting unsaturations withinfluoroelastomeric automotive seals. However, only nucleophilic primaryand secondary amines can participate in subsequent Michael additionreactions with unsaturations that lead to crosslinking reactions andultimately seal embrittlement and failure. Tertiary amines are notcapable of Michael addition reactions due to absence of replaceablehydrogens on nitrogen. Thus, for conventional dispersants that containprimary and secondary amines, greater nitrogen content and higher treatrates of the dispersant, which are generally desirable to promote enginecleanliness over extended service periods, will be more aggressive tothe fluoroelastomer seals.

Methods for improving the compatibility of conventional PIBSIdispersants with automotive seals include the post-treatment ofdispersants to render nucleophilic primary and secondary aminesunreactive or to limit diffusion of the dispersant into the seals, forexample, by increasing the steric bulkiness of the dispersant.

Polyolefin dispersants that include one or more tertiary amines but lackprimary and secondary amines are described herein. The polyolefindispersants can be formed via post-polymerization modification ofpolyolefins. For example, the polyolefin dispersants can be derived frompolyolefin substrates bearing a leaving group (e.g., a halogen) that isreadily displaceable by nucleophilic compounds without competingelimination. Suitable primary halogen-terminated polyolefins can beprepared, for example, via in situ chain end functionalization of livingcarbocationic polyolefins by direct addition of alkoxybenzenederivatives to a living polymerization, or alternatively, to apre-formed tert-chloride-terminated polyolefin activated by a Lewisacid, or alternatively to an olefin-terminated polyolefin activated by aprotic/Lewis acid combination. Because the polyolefin dispersantsinclude one or more tertiary amines and no primary amines or secondaryamines, they cannot participate in crosslinking reactions withfluoroelastomers. As a consequence, the polyolefin dispersants canexhibit increased compatibility towards automotive seals.

For example, provided herein are polyolefin dispersants defined byFormula I below

where R^(x) is an initiator residue; R^(a) is a polyolefin group; R¹ andR² are each, independently in each —(CR¹R²) unit, H, alkyl, alkoxy, oralkylaryl; R³ and R⁴ are each, independently, H, alkyl, or alkoxy; m isan integer from 1 to 20; n is an integer from 1 to 6; r is an integerfrom 1 to 4; Y is a polyvalent amine linker comprising one or moretertiary amines, wherein the polyvalent amine linker does not include aprimary amine or a secondary amine; and A is absent, or comprises adispersive moiety.

In some embodiments, the dispersant can be defined by Formula IA below

wherein R^(x), R^(a), R¹, R², R³, R⁴, m, n, r, Y, and A are defined asdefined above in Formula I.

In some embodiments, R^(a) can comprise a polyisobutylene group. In someembodiments, the polyolefin dispersant can be a dispersant for use inlubricating oils, and R^(a) can have a molecular weight of from 1,000 Dato 2,500 Da (e.g., from 1,000 Da to 2,000 Da; from 1,500 Da to 2,500 Da,from 1,500 Da to 2,000 Da, from 2,000 Da to 2,500 Da). In otherembodiments, the polyolefin dispersant can be an additive for use in ahydrocarbon fuel, and R^(a) can have a molecular weight of less than1,000 Da (e.g., from 100 Da to less than 1,000 Da; from 200 Da to 900Da, from 100 Da to 500 Da, from 500 Da to less than 1,000 Da, from 250Da to less than 1,000 Da, or from 750 to less than 1,000 Da).

In some embodiments, m can an integer from 1 to 10 (e.g., an integerfrom 1 to 8, an integer from 1 to 6, or an integer from 1 to 4).

In some embodiments, R¹ and R² can be, independently for eachoccurrence, H or alkyl (e.g., a C₁-C₆ alkyl group). In certainembodiments, R¹ and R² are H in all occurrences.

In some embodiments, R³ and R⁴ are both positioned ortho on the phenylring relative to R^(a). In other embodiments, R³ and R⁴ are bothpositioned meta on the phenyl ring relative to R^(a). In certainembodiments, R³ and R⁴ are both H.

Y can be any suitable polyvalent amine linker that includes one or moretertiary amines, and does not include a primary amine or a secondaryamine. In some embodiments, Y can comprise from 2 to 30 carbon atoms(e.g., from 4 to 30 carbon atoms, from 6 to 30 carbon atoms, from 6 to20 carbon atoms, from 6 to 15 carbon atoms, or from 6 to 10 carbonatoms).

The number of tertiary amines present in Y can be varied to influencethe dispersive properties of the resulting polyolefin dispersant. Forexample, in some embodiments, the polyvalent amine linker can include atleast 1 tertiary amine (e.g., at least 2 tertiary amines, at least 3tertiary amines, at least 4 tertiary amines, at least 5 tertiary amines,at least 6 tertiary amines, or at least 7 tertiary amines). In someembodiments the polyvalent amine linker can include 8 tertiary amines orless (e.g., 7 tertiary amines or less, 6 tertiary amines or less, 5tertiary amines or less, 4 tertiary amines or less, 3 tertiary amines orless, or 2 tertiary amines or less).

The polyvalent amine linker can include a number of tertiary aminesranging from any of the minimum values described above to any of themaximum values described above. For example, in some embodiments, Y caninclude from 1 to 8 tertiary amines (e.g., from 2 to 8 tertiary amines,from 1 to 6 tertiary amines, from 2 to 6 tertiary amines, from 1 to 4tertiary amines, from 2 to 4 tertiary amines, or from 1 to 3 tertiaryamines).

In some embodiments, Y can comprise a bivalent amine linker and n canbe 1. For example, in some embodiments, Y can be defined by thestructure below

where R⁷ and R⁸ are each, independently in each —(CR¹R²) unit, H, alkyl,alkoxy, or alkylaryl; and b is an integer from 1 to 20 (e.g., an integerfrom 1 to 10, an integer from 1 to 8, an integer from 1 to 6, or aninteger from 1 to 4). In some of these embodiments, R⁷ and R⁸ can bothbe, in each occurrence, H.

In other embodiments, Y can be defined by the structure below

where R⁷ and R⁸ are each, independently for each occurrence, H, alkyl,alkoxy, or alkylaryl; and b is, independently for each occurrence, aninteger from 1 to 20 (e.g., an integer from 1 to 10, an integer from 1to 8, an integer from 1 to 6, or an integer from 1 to 4). In some ofthese embodiments, R⁷ and R⁸ can both be, in each occurrence, H. In someof these embodiments, b is, in each occurrence, 2.

In other embodiments, Y can comprise a trivalent amine linker and n canbe 2. For example, in some embodiments, Y can be defined by thestructure below

where R⁷ and R⁸ are each, independently in each —(CR¹R²) unit, H, alkyl,alkoxy, or alkylaryl; and b is an integer from 1 to 20 (e.g., an integerfrom 1 to 10, an integer from 1 to 8, an integer from 1 to 6, or aninteger from 1 to 4). In some of these embodiments, R⁷ and R⁸ can bothbe, in each occurrence, H.

In some embodiments, A is absent, and Y can be defined by the structurebelow

where c is an integer from 1 to 6. In some of these embodiments, c canbe 1. In other of these embodiments, c can be 2.

In some embodiments, A is absent, and Y can be defined by the structurebelow

where R⁹ is alkyl, cycloalkyl, alkoxy, aryl, heteroaryl, alkylaryl,alkylcycloalkyl or heteroarylalkyl. In certain embodiments, R⁹ can bearyl or heteroaryl. In certain embodiments, R⁹ can be phenyl. In otherembodiments, R⁹ can be pyridyl. For example, in one embodiment, A can beabsent and Y can be defined by the structure below

In some embodiments, A is absent, and Y can be defined by the structurebelow

where R⁷ and R⁸ are each, independently for each occurrence, H, alkyl,alkoxy, or alkylaryl; R⁹ is alkyl, cycloalkyl, alkoxy, aryl, heteroaryl,alkylaryl, alkylcycloalkyl or heteroarylalkyl; and b is, independentlyfor each occurrence, an integer from 1 to 20 (e.g., an integer from 1 to10, an integer from 1 to 8, an integer from 1 to 6, or an integer from 1to 4). In some of these embodiments, R⁷ and R⁸ can both be, in eachoccurrence, H. In some of these embodiments, b is, in each occurrence,2. In some of these embodiments, R⁹ can be aryl or heteroaryl. In someof these embodiments, R⁹ can be phenyl. In some of these embodiments, R⁹can be pyridyl.

In some embodiments, A is absent. In other embodiments, A is present.When present, A can be any suitable dispersive moiety. Dispersivemoieties include chemical moieties that have an affinity for the surfaceof soot particles. Examples of such chemical moieties are known in theart, and include, for example, moieties that are able to participate inn-nt interactions with the surface of soot (e.g., aromatic groups).Other examples of dispersive moieties include chemical moieties that canbe formed by reaction of a primary amine with a reactive functionalgroup (e.g., an isocyanate, or a carbonyl, such as a carboxylic acid,acyl halide, or aldehyde).

In some embodiments, A can comprise an imide moiety. In certainembodiments, the imide can comprise a cyclic imide. For example, in somecases the imide moiety can comprise a moiety defined by Formula IIIbelow

where R⁵, R⁶, and R⁷ are each, independently, H, halogen, alkyl, alkoxy,aryl, alkylaryl, or cycloalkyl; or wherein R⁵ and R⁶, together with theatoms to which they are attached, R⁶ and R⁷, together with the atoms towhich they are attached, or both R⁵ and R⁶ and R⁶ and R⁷, together withthe atoms to which they are attached, form a 5-8 membered substituted orunsubstituted aromatic or non-aromatic ring. For example, the imidemoiety comprises one of the following

In other embodiments, the imide moiety can comprise a moiety defined byFormula IV below

where R⁵ and R⁶ are each, independently, H, halogen, alkyl, alkenyl,alkoxy, aryl, alkylaryl, or cycloalkyl, or wherein R⁵ and R⁶, togetherwith the atoms to which they are attached, form a 5-8 memberedsubstituted or unsubstituted aromatic or non-aromatic ring. In someembodiments, the imide moiety can comprise one of the following

In one embodiment of Formula IV, R⁵ can be an alkyl group and R⁶ can beH. In one embodiment of Formula IV, R⁵ can be a polyolefin group (e.g.,a polyisobutylene group) and R⁶ can be H.

In some embodiments, A can comprise a diimide moiety or a polyimidemoiety. For example, in some embodiments, the polyolefin dispersant canbe defined by Formula IB below

where R^(x) is an initiator residue; R^(a) is a polyolefin group; R¹ andR² are each, independently in each —(CR¹R²) unit, H, alkyl, alkoxy, oralkylaryl; R³ and R⁴ are each, independently, H, alkyl, or alkoxy; m isan integer from 1 to 20; n is an integer from 1 to 100; r is an integerfrom 1 to 4; Y is a polyvalent amine linker comprising one or moretertiary amines, wherein the polyvalent amine linker does not include aprimary amine or a secondary amine; and A is absent, or comprises adiimide moiety or a polyimide moiety.

For example, in some embodiments, A can comprise a diimide moiety. Forexample, the diimide moiety can comprise an aromatic system substitutedwith two cyclic imide groups.

The aromatic system can be a single aromatic ring (e.g., a phenyl ringsubstituted with two cyclic imide groups), a fused aromatic system(e.g., a naphthalene, anthracene, or perylene ring substituted with twocyclic imide groups), or two aromatic rings or fused aromatic systemslinked together, each of which is substituted with a cyclic imide groups(e.g., a biphenyl, binaphthalene, or benzophenone in which each aromaticring or fused aromatic system is substituted with a cyclic imide group).In certain embodiments, the polyolefin dispersant can be defined by thegeneral structure shown below

where R^(x), R^(a), R¹, R², m, and Y are defined as defined with respectFormula I.

In other embodiments, A can comprise a polyimide moiety. The polyimidemoiety can comprise a molecular scaffold bearing three or more cyclicimide groups. In some embodiments, the molecular scaffold can comprisean aromatic system substituted with three or more cyclic imide groups.In some embodiments, the molecular scaffold can comprise a polymersubstituted with three or more cyclic imide groups (e.g., a polymer orcopolymer bearing three or more cyclic imide groups as sidechains and/oralong the polymer backbone). For example, in certain embodiments, thepolyolefin dispersant can be a polymer or copolymer that comprises amonomer defined by the general structure shown below

where R^(x), R^(a), R¹, R², m, and Y are defined as defined with respectFormula I. In certain embodiments, the polyolefin dispersant can be acopolymer that comprises a monomer defined by the general structureabove and one or more additional monomers derived from polymerization ofan ethylenically-unsaturated monomer. Examples of suitableethylenically-unsaturated monomers include meth(acrylate) monomers,vinyl aromatic monomers having up to 20 carbon atoms (e.g., styrene),vinyl esters of carboxylic acids comprising up to 20 carbon atoms,(meth)acrylonitriles, vinyl halides, vinyl ethers of alcohols comprising1 to 10 carbon atoms, aliphatic hydrocarbons having 2 to 8 carbon atomsand one or two double bonds, (meth)acrylamides, (meth)acrylamidederivatives, and combination of these monomers. As used herein,“(meth)acryl . . . ” includes acryl . . . , methacryl . . . , diacryl .. . , and dimethacryl . . . . For example, the term “(meth)acrylatemonomer” includes acrylate, methacrylate, diacrylate, and dimethacrylatemonomers. Meth)acrylate monomers can include esters ofα,β-monoethylenically unsaturated monocarboxylic and dicarboxylic acidshaving 3 to 6 carbon atoms with alkanols having 1 to 12 carbon atoms(e.g., esters of acrylic acid, methacrylic acid, maleic acid, fumaricacid, or itaconic acid, with C₁-C₂₀, C₁-C₁₂, C₁-C₈, or C₁-C₄ alkanols).

In some embodiments, R^(x) can comprise a multi-functional initiatorresidue, and r can be an integer from 2 to 4. In some cases, R^(x) cancomprise a bi-functional initiator residue, and r can be 2. In theseembodiments, the polyolefin dispersant can be defined by the generalstructure shown below

where R^(x), R^(a), R¹, R², R³, R⁴, m, n, Y, and A are defined asdefined above in Formula I. In some of these embodiments, the polyolefindispersant can be defined by the general structure shown below

where R^(x), R^(a), R¹, R², R³, R⁴, m, n, Y, and A are defined asdefined above in Formula I.

Examples of bi-functional initiator residues include, for example,initiator residues derived from 1,3-di(1-chloro-1-methylethyl)benzene,1,3-di(1-methoxy-1-methylethyl)benzene,1,4-di(1-chloro-1-methylethyl)benzene,1,4-di(1-methoxy-1-methylethyl)benzene,1,3-di(1-chloro-1-methylethyl)-5-tert-butylbenzene,1,3-di(1-methoxy-1-methylethyl)-5-tert-butylbenzene,2,6-dichloro-2,4,4,6-tetramethylheptane, and2,6-dimethoxy-2,4,4,6-tetramethylheptane. In some embodiments, thebi-functional initiator residue can be an initiator residue derived from1,3-di(1-chloro-1-methylethyl)-5-tert-butylbenzene or2,6-dichloro-2,4,4,6-tetramethylheptane. In certain embodiments, thebi-functional initiator residue can be an initiator residue derived from1,3-di(1-chloro-1-methylethyl)-5-tert-butylbenzene.

In other cases, R^(x) can comprise a tri-functional initiator residue,and r can be 3. In these embodiments, the polyolefin dispersant can bedefined by the general structure shown below

where R^(x), R^(a), R¹, R², R³, R⁴, m, n, Y, and A are defined asdefined above in Formula I. In some of these embodiments, the polyolefindispersant can be defined by the general structure shown below

where R^(x), R^(a), R¹, R², R³, R⁴, m, n, Y, and A are defined asdefined above in Formula I.

Examples of tri-functional initiator residues include, for example,initiator residues derived from1,3,5-tri(1-chloro-1-methylethyl)benzene,1,3,5-tri(1-bromo-1-methylethyl)benzene, or1,3,5-tri(1-methoxy-1-methylethyl)benzene.

In other embodiments, R^(x) can comprise a mono-functional initiatorresidue, and r is 1. In such embodiments, the dispersant can be definedby Formula IB below

wherein R^(x), R^(a), R¹, R², R³, R⁴, m, n, Y, and A are defined asdefined above in Formula I. In some of these embodiments, the dispersantcan be defined by Formula II below

wherein R^(x), R^(a), R¹, R² m, n, Y, and A are defined as defined abovein Formula I.

Examples of mono-functional initiator residues include, for example,initiator residues derived from 2-chloro-2-phenylpropane,2-acetoxy-2-phenylpropane, 2-propionyloxy-2-phenylpropane,2-methoxy-2-phenylpropane, 2-ethoxy-2-phenylpropane,2-chloro-2,4,4-trimethylpentane, 2-acetoxy-2,4,4,-trimethylpentane,2-propionyloxy-2,4,4-trimethylpentane, 2-methoxy-2,4,4-trimethylpentane,2-ethoxy-2,4,4-trimethylpentane, 2-chloro-2,4,4,6,6-pentamethylheptane,2-acetoxy-2,4,4,6,6-pentamethylheptane,2-propionyloxy-2,4,4,6,6-pentamethylheptane,2-methoxy-2,4,4,6,6-pentamethylheptane, and2-ethoxy-2,4,4,6,6-pentamethylheptane. In certain embodiments, themono-functional initiator residue can be an initiator residue derivedfrom 2-chloro-2,4,4-trimethylpentane.

Methods

The polyolefin dispersants described herein can be formed viapost-polymerization modification of polyolefins using inexpensivereagents and materials. For example, the polyolefin dispersants can bederived from polyolefin substrates bearing a leaving group (e.g., ahalogen) that is readily displaceable by nucleophilic compounds withoutcompeting elimination. Suitable primary halogen-terminated polyolefinscan be prepared, for example, via in situ chain end functionalization ofliving carbocationic polyolefins by direct addition of alkoxybenzenederivatives to a living polymerization, or alternatively, to apre-formed tert-chloride-terminated polyolefin activated by a Lewisacid, or alternatively to an olefin-terminated polyolefin activated by aprotic/Lewis acid combination. Other methods for forming suitableprimary halogen-terminated polyolefins are described in Martinez-Castro,N.; Morgan, D. L.; Storey, R. F. Macromolecules 2009, 42, 4963-4971,which is incorporated by reference herein.

In some embodiments, methods for preparing polyolefin dispersants cancomprise (a) generating a quasiliving polyolefin in a reversibledeactivation-type living polymerization; (b) adding to the reversibledeactivation-type living polymerization of step (a) a quenching agentdefined by Formula V to generate a phenoxy-quenched precursor;

wherein R¹, R², R³, R⁴, and m are as defined above with respect toFormula I, and X is a leaving group; (c) reacting the phenoxy-quenchedprecursor with a polyamine to form a polyamine-capped precursor; and (d)reacting the polyamine-capped precursor with an anhydride to form thepolyolefin dispersant.

Methods of generating quasiliving polyolefins in reversibledeactivation-type living polymerizations are known in the art.Non-limiting examples of such methods are described in WO 2006/110647A1, both of which are incorporated by reference herein. In someembodiments, the reversible deactivation-type living polymerization canbe a reversible deactivation-type living carbocationic polymerization,also referred to as a quasiliving carbocationic polymerization.

In some embodiments, a monomer, an initiator, and a Lewis acid are used.In some embodiments, an electron donor, common ion salt, and/or commonion salt precursor is/are used. In some embodiments, the ionizedpolyolefin is a quasiliving carbocationic polyisobutylene. In someembodiments, the quasiliving carbocationic polyolefin can be generatedfrom a preformed polyolefin.

In some embodiments, step (a) can comprise combining a Lewis acid and amonomer with an initiator in the presence of an electron donor, commonion salt, common ion salt precursor, or combination thereof.

In some embodiments, the Lewis acid can be a non-protic acid. In someembodiments, the Lewis acid can be a metal halide or non-metal halide.In certain embodiments, the Lewis acid is a metal halide. For example,the Lewis acid can be a titanium (IV) halide (e.g., titaniumtetrabromide, titanium tetrachloride), a zinc (II) halide (e.g., zincchloride), a tin (IV) halide, or an aluminum (III) halide (e.g.,aluminum trichloride, ethyl aluminum dichloride, methyl aluminumdichloride). In certain embodiments, the Lewis acid can be an antimony(VI) halide, a gallium (III) halide, or a boron (III) halide (e.g.,boron trichloride). Other suitable Lewis acids include trialkyl aluminumcompounds, such as trimethyl aluminum. In some cases, a single Lewisacid can be used. In other cases, a mixture of two or more Lewis acidscan be used.

The initiator can be a compound or polyolefin with one, or more thanone, end group capable of initiating a cationic olefin polymerization.For example, the initiator can be a compound of formula(X′—CR^(a)R^(b))_(r)R^(c) wherein R^(a) and R^(b) are independentlyhydrogen, alkyl, aryl, alkaryl, or aralkyl, provided that at least oneof R^(a) or R^(b) is not hydrogen; R^(c) is an aliphatic or aromaticunivalent or polyvalent radical with valence r, wherein r is an integerfrom one to 4; and X′ is acyl, alkoxy, hydroxy, or halogen. In someembodiments, R^(a), R^(b), and R^(c) are hydrocarbon groups containingone carbon atom to about 20 carbon atoms. In some embodiments, R^(a),R^(b), and R^(c) are hydrocarbyl groups containing one carbon atom toabout 8 carbon atoms. In some embodiments, X′ is a halogen. In someembodiments, X′ is chloride. In some embodiments, the structure ofR^(a), R^(b), and R^(c) mimics the growing species or monomer. In someembodiments, the structure is a 1-halo-1-tolylethane initiator forpolystyrene or a 2-halo-2,4,4-trimethyl pentane initiator forpolyisobutylene. In some embodiments, R^(a), R^(b), and R^(c) are eachhydrocarbon groups containing one carbon atom to about 10 carbon atomsfor the initiation of an isobutylene polymerization. In someembodiments, the initiator is a cumyl, dicumyl or tricumyl halide. Insome embodiments, r is 1 or 2.

Examples of suitable initiators include 2-chloro-2-phenylpropane, i.e.,cumyl chloride; 1,4-di(1-chloro-1-methylethyl)benzene, i.e.,di(cumylchloride); 1,3,5-tri(1-chloro-1-methylethyl)benzene, i.e.,tri(cumylchloride); 2-acetoxy-2-phenylpropane, i.e., cumyl acetate;2-propionyloxy-2-phenyl propane, i.e., cumyl propionate;2-methoxy-2-phenylpropane, i.e., cumyl methyl ether;1,4-di(1-methoxy-1-methylethyl)benzene, i.e., di(cumyl methyl ether);1,3,5-tri(1-methoxy-1-methylethyl)benzene, i.e., tri(cumyl methylether); 2-chloro-2,4,4-trimethyl pentane (TMPCl);2-chloro-2,4,4,6,6-pentamethylheptane (PMHCl);1,3-di(1-chloro-1-methylethyl)benzene;2,6-dichloro-2,4,4,6-tetramethylheptane; and1,3,-di(1-chloro-1-methylethyl)-5-tert-butylbenzene (bDCC).

The initiator can be mono-functional, bi-functional, ormulti-functional. Examples of suitable mono-functional initiatorsinclude 2-chloro-2-phenylpropane, 2-acetoxy-2-phenylpropane,2-propionyloxy-2-phenylpropane, 2-methoxy-2-phenylpropane,2-ethoxy-2-phenylpropane, 2-chloro-2,4,4-trimethylpentane,2-acetoxy-2,4,4,-trimethylpentane,2-propionyloxy-2,4,4-trimethylpentane, 2-methoxy-2,4,4-trimethylpentane,2-ethoxy-2,4,4-trimethylpentane, 2-chloro-2,4,4,6,6-pentamethylheptane,2-acetoxy-2,4,4,6,6-pentamethylheptane,2-propionyloxy-2,4,4,6,6-pentamethylheptane,2-methoxy-2,4,4,6,6-pentamethylheptane, and2-ethoxy-2,4,4,6,6-pentamethylheptane. In some embodiments, theinitiator can be 2-chloro-2,4,4-trimethylpentane. Examples of suitablebi-functional initiators include 1,3-di(1-chloro-1-methylethyl)benzene,1,3-di(1-methoxy-1-methylethyl)benzene,1,4-di(1-chloro-1-methylethyl)benzene,1,4-di(1-methoxy-1-methylethyl)benzene,1,3-di(1-chloro-1-methylethyl)-5-tert-butylbenzene,1,3-di(1-methoxy-1-methylethyl)-5-tert-butylbenzene,2,6-dichloro-2,4,4,6-tetramethylheptane, or2,6-dimethoxy-2,4,4,6-tetramethylheptane. In some embodiments, theinitiator is 1,3-di(1-chloro-1-methylethyl)-5-tert-butylbenzene or2,6-dichloro-2,4,4,6-tetramethylheptane. In some embodiments, theinitiator can be 1,3-di(1-chloro-1-methylethyl)-5-tert-butylbenzene.Examples of suitable multi-functional (tri-functional) initiatorsinclude 1,3,5-tri(1-chloro-1-methylethyl)benzene,1,3,5-tri(1-bromo-1-methylethyl)benzene, or1,3,5-tri(1-methoxy-1-methylethyl)benzene.

The monomer can be a hydrocarbon monomer, i.e., a compound containingonly hydrogen and carbon atoms, including but not limited to, olefinsand diolefins, and those having from about 2 to about 20 carbon atoms.In some embodiments, such compounds have from about 4 to about 8 carbonatoms. Examples of suitable monomers include isobutylene, styrene,beta-pinene, isoprene, butadiene, or substituted compounds of thepreceding types. In some embodiments, the monomer is isobutylene,2-methyl-1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, or styrene. Insome embodiments, the monomer is isobutylene. If desired for aparticular application, mixtures of monomers can be used.

If desired, electron donors can be used in conjunction with thereversible deactivation-type living polymerizations described herein. Insome embodiments, the electron donor can be capable of complexing withLewis acids. In some embodiments, the electron donor can be a baseand/or nucleophile. In some embodiments, the electron donor can becapable of abstracting or removing a proton. In some embodiments, theelectron donor can be an organic base. In some embodiments, the electrondonor can be an amide (e.g., N,N-dimethylformamide,N,N-dimethylacetamide, or N,N-diethylacetamide). In some embodiments,the electron donor can be a sulfoxide (e.g., dimethyl sulfoxide). Insome embodiments, the electron donor can be an ester (e.g., methylacetate or ethyl acetate). In some embodiments, the electron donor canbe a phosphate compound (e.g., trimethyl phosphate, tributyl phosphate,or triamide hexamethylphosphate). In some embodiments, the electrondonor can be an oxygen-containing metal compound (e.g., tetraisopropyltitanate). In some embodiments, the electron donor is pyridine or apyridine derivative (e.g., 2,6-di-tert-butylpyridine, 2,6-lutidine,2,4-lutidine, 2,4,6-trimethylpyridine, 2-methylpyridine, or pyridine).Other suitable electron donors include N,N-dimethylaniline orN,N-dimethyltoluidine.

If desired, common ion salts or salt precursors may be optionally addedto the reaction mixture in addition to or in replacement of the electrondonor. In some embodiments, such salts may be used to increase the ionicstrength, suppress free ions, and interact by ligand exchange. Examplesof suitable common ion salts or salt precursors includetetra-n-butylammonium chloride, tetra-n-butylammonium bromide,tetra-n-butylammonium iodide.

Step (b) can comprise adding to the reversible deactivation-type livingpolymerization of step (a) a quenching agent defined by Formula V togenerate a phenoxy-quenched precursor. In some embodiments, step (b) isperformed for about 5 minutes to about 120 minutes. In some embodiments,step (b) is performed for about 15 minutes to about 90 minutes. In someembodiments, step (b) is performed for about 30 minutes to about 60minutes.

In some embodiments, prior to step (b), the reversible deactivation-typeliving polymerization of step (a) is terminated and subsequentlyreactivated zero, one, or more times at a desired time. In someembodiments, the reversible deactivation-type living polymerization ofstep (a) is terminated and subsequently reactivated zero times, i.e.,after generation of the quasiliving polyolefin of step (a), thereversible deactivation-type living polymerization of step (a) is notterminated at any time prior to step (b). In some embodiments, thereversible deactivation-type living polymerization of step (a) isterminated and subsequently reactivated one time.

In some embodiments, the quenching agent defined by Formula V is addedafter high conversion of the monomer. In particular embodiments, thequenching agent defined by Formula V is added after 80%, 85%, 90%, 95%,97%, 99%, or 99.9% of the monomer has been polymerized into thequasiliving polyolefin.

Step (c) can comprise reacting the phenoxy-quenched precursor with apolyamine to form a polyamine-capped precursor. Examples of suitablepolyamines include 1-(2-aminoethyl)piperazine,4-[2-(1-piperazinyl)ethyl]-1-piperazineethanamine, diethylenetriamine,N-methyl-1,3-diaminopropane, triethylenetetramine (TETA),triethylenepentamine (TEPA), pentaethylenehexamine (PEHA),hexaethyleneheptamine (HEHA), N-phenyl-p-phenylenediamine, andN-benzylethylenediamine.

If necessary to control reactivity of the polyamine with thephenoxy-quenched precursor, one or more amine groups of the polyaminecan be protected prior to reaction with the phenoxy-quenched precursor.A wide variety of amine protecting groups are known in the art, and maybe selected based on the overall structure of the polyamine as well asthe structure of the phenoxy-quenched precursor. See, for example,Greene, et al., Protective Groups in Organic Synthesis, John Wiley andSons, Third Edition, 1999, hereby incorporated by reference. By way ofexample, protection of primary amines within a polyamine can beaccomplished by reaction of the polyamine with an excess of a ketone,for example, methyl isobutyl ketone (MIBK), at reflux to form the iminederivative (Schiff base) while leaving the secondary and tertiary aminesintact. In these embodiments, step (c) can comprise reacting thephenoxy-quenched precursor with the protected polyamine to form aprotected polyamine-capped precursor, and deprotecting the protectedpolyamine-capped precursor to form the polyamine-capped precursor.

Step (d) can comprise reacting the polyamine-capped precursor with ananhydride to form the polyolefin dispersant. Any suitable anhydride canbe used. In some embodiments, the anhydride can comprise a cyclicanhydride.

For example, in some cases the anhydride can comprise a cyclic anhydridedefined by the structure below

where R⁵, R⁶, and R⁷ are each, independently, H, halogen, alkyl, alkoxy,aryl, alkylaryl, or cycloalkyl; or wherein R⁵ and R⁶, together with theatoms to which they are attached, R⁶ and R⁷, together with the atoms towhich they are attached, or both R⁵ and R⁶ and R⁶ and R⁷, together withthe atoms to which they are attached, form a 5-8 membered substituted orunsubstituted aromatic or non-aromatic ring. For example, the anhydridecan comprise one of the following

In other embodiments, the anhydride can comprise a cyclic anhydridedefined by the structure below

where R⁵ and R⁶ are each, independently, H, halogen, alkyl, alkoxy,aryl, alkylaryl, or cycloalkyl, or wherein R⁵ and R⁶, together with theatoms to which they are attached, form a 5-8 membered substituted orunsubstituted aromatic or non-aromatic ring. For example, the anhydridecan comprise one of the following

Other suitable anhydrides include, for example, dianhydrides. Examplesof suitable dianhydrides include pyromellitic dianhydride; dianhydridesderived from fused aromatic systems, such asnaphthalene-2,3,6,7-tetracarboxylic acid dianhydride, naphthalene-1,2,5,6-tetracarboxylic acid dianhydride andperylene-3,4,9,10-tetracarboxylic acid dianhydride, and dianhydrideswherein the anhydride groups are attached to different aromatic (e.g.,benzene) rings which are linked together, such asdiphenyl-3,3,4,4-tetracarboxylic acid dianhydride, diphenyl-2,2′,3,3′-tetracarboxylic acid dianhydride,2,2-bis(3,4-dicarboxyphenyl(propane dianhydride,bis(3,3-dicarboxyphenyl) ether dianhydride, bis(3,4dicarboxyphenyl)sulphone dianhydride, benzophenone-2,2,3,3′-tetracarboxylic aciddianhydride and benzophenone 3,3,4,4-tetracarboxylic acid dianhydride.In certain embodiments, the dianhydride can comprise pyromelliticdianhydride. In certain embodiments, the dianhydride can comprise anaphthalenetetracarboxylic dianhydride.

Other suitable anhydrides include polycyclic anhydrides. The polycyclicanhydride can comprise a molecular scaffold bearing three or more cyclicanhydrides groups. In some embodiments, the molecular scaffold cancomprise an aromatic system substituted with three or more cyclicanhydride groups. In some embodiments, the molecular scaffold cancomprise a polymer substituted with three or more cyclic anhydridegroups (e.g., a polymer or copolymer bearing three or more cyclicanhydride groups as sidechains and/or along the polymer backbone). Forexample, in some embodiments, the polycyclic anhydride can be a polymeror copolymer comprising maleic anhydride monomer units. In certainembodiments, the polycyclic anhydride can be a copolymer that comprisesmaleic anhydride monomers and one or more additional monomers derivedfrom polymerization of an ethylenically-unsaturated monomer. Examples ofsuitable ethylenically-unsaturated monomers include meth(acrylate)monomers, vinyl aromatic monomers having up to 20 carbon atoms (e.g.,styrene), vinyl esters of carboxylic acids comprising up to 20 carbonatoms, (meth)acrylonitriles, vinyl halides, vinyl ethers of alcoholscomprising 1 to 10 carbon atoms, aliphatic hydrocarbons having 2 to 8carbon atoms and one or two double bonds, (meth)acrylamides,(meth)acrylamide derivatives, and combination of these monomers. As usedherein, “(meth)acryl . . . ” includes acryl . . . , methacryl . . . ,diacryl . . . , and dimethacryl . . . . For example, the term“(meth)acrylate monomer” includes acrylate, methacrylate, diacrylate,and dimethacrylate monomers. Meth)acrylate monomers can include estersof α,β-monoethylenically unsaturated monocarboxylic and dicarboxylicacids having 3 to 6 carbon atoms with alkanols having 1 to 12 carbonatoms (e.g., esters of acrylic acid, methacrylic acid, maleic acid,fumaric acid, or itaconic acid, with C1-C20, C1-C12, C1-C8, or C1-C4alkanols). By way of example, in some cases the polycyclic anhydride canbe poly(styrene-alt-maleic anhydride)).

Lubricating Oil Compositions

As discussed above, the polyolefin dispersants described herein can beused as detergent and dispersant additives in lubricating oils. Whenemployed in this manner, the polyolefin dispersants are usually presentin the lubricant oil composition in an amount of from 0.2 to 10 percentby weight (e.g., from 0.5 to 8 percent by weight, or from 1 to 6 percentby weight), based on the total weight of the lubricant oil composition.The lubricating oil in these compositions may be, for example, mineraloil or synthetic oils of lubricating viscosity. In certain embodiments,the lubricating oil can be an oil that is suitable for use in thecrankcase of an internal combustion engine. Crankcase lubricating oilsordinarily have a viscosity of about 1300 CSt 0° F. to 22.7 CSt at 210°F. (99° C.). The lubricating oils may be derived from synthetic ornatural sources. Mineral oil for use as the base oil can includeparaffinic, naphthenic and other oils that are ordinarily used inlubricating oil compositions. Synthetic oils include both hydrocarbonsynthetic oils and synthetic esters. Useful synthetic hydrocarbon oilsinclude liquid polymers of alpha olefins having the proper viscosity.Especially useful are the hydrogenated liquid oligomers of C₆ to C₁₂alpha olefins such as 1-decene trimer. Likewise, alkyl benzenes ofproper viscosity, such as didodecyl benzene, can be used. Blends ofhydrocarbon oils with synthetic oils are also useful.

Also provided are lubricating oil concentrates. The concentrates caninclude from 90 to 10 weight percent, (e.g., from 90 to 50 weightpercent) of an oil of lubricating viscosity, based on the total weightof the concentrate composition, and from 10 to 90 weight percent (e.g.,from 10 to 50 weight percent), of a polyolefin dispersant describedherein, based on the total weight of the concentrate composition.Typically, the concentrates contain sufficient diluent to make them easyto handle during shipping and storage. Suitable diluents for theconcentrates include any inert diluent, preferably an oil of lubricatingviscosity, such that the concentrate may be readily mixed withlubricating oils to prepare lubricating oil compositions.

Suitable lubricating oils which can be used as diluents typically haveviscosities in the range from about 35 to about 500 Saybolt UniversalSeconds (SUS) at 100° F. (38° C.), although an oil of lubricatingviscosity may be used.

Other additives that can be included in the lubricating oil compositionsinclude rust inhibitors, foam inhibitors, corrosion inhibitors, metaldeactivators, pour point depressants, antioxidants, and a variety ofother well-known additives. It is also contemplated the polyolefindispersants described herein be employed as dispersants and detergentsin hydraulic fluids, marine crankcase lubricants, and the like. When soemployed, the polyolefin dispersants can be present in an amount of from0.1 to 10 weight percent (e.g., from 0.5 to 8 weight percent) by weightto the oil.

Fuel Compositions

The polyolefin dispersants described herein can also be used as fueladditives. When used in fuels, the proper concentration of the additivenecessary in order to achieve the desired detergency is dependent upon avariety of factors including the type of fuel used, the presence ofother detergents or dispersants or other additives, etc. Generally,however, the range of concentration of the polyolefin dispersants in thebase fuel can be from 10 to 10,000 weight parts per million (e.g., from30 to 5000 parts per million weight parts per million) base fuel. Ifother detergents are present in the composition, a lesser amount of theadditive may be used.

The polyolefin dispersants may be formulated as a fuel concentrate,using an inert stable oleophilic organic solvent boiling in the range offrom 150° F. to 400° F. In some cases, an aliphatic or an aromatichydrocarbon solvent is used, such a benzene, toluene, xylene orhigher-boiling aromatics or aromatic thinners. Aliphatic alcohols ofabout 3 to 8 carbon atoms, such as isopropanol, isobutylcarbinol,n-butanol and the like, in combination with hydrocarbon solvents arealso suitable for use with the fuel additive. In the fuel concentrate,the polyimide will be ordinarily at least 5 percent by weight andgenerally not exceed 70 percent by weight, preferably from 5 to 50 andmore preferably from 10 to 25 weight percent.

By way of non-limiting illustration, examples of certain embodiments ofthe present disclosure are given below.

EXAMPLES

Materials and Methods

Hexane (anhydrous, 95%), titanium tetrachloride (TiCl₄) (99.9%),2,6-lutidine (redistilled, 99.5%), (3-bromopropoxy)benzene (96%),tetrahydrofuran (THF) (anhydrous, 99.9%), methanol (anhydrous, 99.8%),acetone (anhydrous, 99%), methyl isobutyl ketone (99%),1-(2-aminoethyl)piperazine (99%), phthalic anhydride (99%),1,8-naphthalic anhydride (99%), glutaric anhydride (95%), maleicanhydride (99%), cumene-terminated poly(styrene-co-maleic anhydride)(M_(n)≈1,600 g-mol⁻¹, acid number: 465-496 mg KOH/g), silvertrifluoroacetic acid (AgTFA), sodium trifluoroacetate (NaTFA) (98%),dithranol (98.5%), diethylenetriamine (DETA, 99%), methylene chloride-d₂(CD₂Cl₂) (99.8%), and chloroform-d (CDCl₃) were purchased fromSigma-Aldrich Co. and used as received. Anhydrous magnesium sulfate(MgSO₄) was purchased and used as received from Fisher Scientific.Isobutylene (IB) (99%) and methyl chloride (99.5%) (both Gas and SupplyCo., Hattiesburg, Miss.) were dried by passing the gaseous reagentthrough a column of CaSO₄/molecular sieves/CaCl₂ and condensing within aN₂-atmosphere glovebox immediately prior to use.trans-2-[3-(4-tert-Butylphenyl)-2-methyl-2-propenylidene]malononitrile(DTCB) was purchased from Tokyo Chemical Industry Co. and used asreceived. 2-Chloro-2,4,4-trimethylpentane (TMPCl) was prepared bybubbling HCl gas through neat 2,4,4-trimethyl-1-pentene (99%,Sigma-Aldrich) at 0° C. The HCl-saturated TMPCl was stored at 0° C. andimmediately prior to use was neutralized with NaHCO₃, dried overanhydrous MgSO₄, and filtered. RLOP 100N Base Oil was provided byChevron Oronite. Vulcan XC-72R was purchased and used as received fromFuel Cell Store.

Nuclear magnetic resonance (NMR) spectra were obtained using a 300 MHzVarian Mercuryplus NMR (VNMR 6.1C) spectrometer. Standard ¹H and ¹³Cpulse sequences were used. Composite pulse decoupling was used to removeproton coupling in ¹³C spectra. All ¹H chemical shifts were referencedto TMS (0 ppm). Samples were prepared by dissolution in CD₂Cl₂ (20-50mg/mL) and charging this solution to a 5 mm NMR tube.

Number-average molecular weights (M_(n)) and polydispersities(PDI=M_(w)/M_(n)) were determined with a gel-permeation chromatography(GPC) system consisting of a Waters Alliance 2695 separations module, anonline multiangle laser light scattering (MALLS) detector fitted with a20 mW laser operating at 658 nm (miniDAWN TREOS, Wyatt Technology Inc.),an interferometric refractometer (Optilab rEX, Wyatt Technology Inc.)operating at 35° C. and 685 nm, and two PLgel (Polymer LaboratoriesInc.) mixed E columns (pore size range 50-103 A°, 3 μm bead size).Freshly distilled THF served as the mobile phase and was delivered at aflow rate of 1.0 mL/min. Sample concentrations were ca. 15-20 mg ofpolymer/mL of THF, and the injection volume was 100 μL. The detectorsignals were simultaneously recorded using ASTRA software (WyattTechnology Inc.), and absolute molecular weights were determined byMALLS using a dn/dc calculated from the refractive index detectorresponse and assuming 100% mass recovery from the columns.

Real-time ATR-FTIR monitoring of isobutylene polymerizations wasperformed using a ReactIR 4000 (Mettler-Toledo) integrated with aN₂-atmosphere glovebox (MBraun Labmaster 130). Isobutylene conversionduring polymerization was determined by monitoring the area, above atwo-point baseline, of the absorbance centered at 887 cm⁻¹, associatedwith the ═CH₂ wag of isobutylene.

Fourier transform infrared spectroscopy (FTIR) was used to determine thepresence of imide groups in the PIB-PzEA-derived dispersants as well asthe lack of anhydride and amic-acid groups. FTIR spectra of thePIB-PzEA-derived dispersants were acquired between sodium chloride saltwindows using a Nicolet 8700 spectrometer and Omnic software. Spectrawere taken with a resolution of 4 cm⁻¹ by accumulating a minimum of 128scans per run. Nitrogen was constantly purged through the attachment toreduce interference of CO₂ and water. Absorbances at 1770 cm⁻¹ and 1710cm⁻¹ were indicative of the presence of imide groups while absence ofstretches at 18600 cm⁻¹ and 1785 cm⁻¹ were indicative of the lack ofanhydride and amic acid groups.

Matrix-assisted laser desorption/ionization time-of-flight massspectrometry (MALDI-TOF MS) was performed using a Bruker Microflex LRFMALDI-TOF mass spectrometer equipped with a nitrogen laser (337 nm)possessing a 60 Hz repetition rate and 50 J energy output. The PIBsamples were prepared using the dried droplet method: separatelyprepared THF solutions of DCTB or dithranol matrix (20 mg/mL), PIBsample (10 mg/mL), and AgTFA or NaTFA cationizing agent (10 mg/mL) weremixed in a volumetric ratio of matrix/sample/cationizing agent=4:1:0.2,and a 0.5 μL aliquot was applied to a MALDI sample target for analysis.The spectrum was obtained in the positive ion mode utilizing theReflector mode microchannel plate detector and was generated as the sumof 900-1000 shots.

Dispersant adsorption onto carbon black via supernatant depletion assaywas carried out with the use of a Perkin Elmer Lambda 35 UV/VISspectrometer. Solutions ranging from 25-0.1 mg/mL of dispersant wereprepared in dodecane followed by the careful addition of 75 mg of VulcanXC-72R carbon black. The solutions were then sealed and vortexed for 15minutes followed by high-speed mixing with the use of a FlackTek speedmixer DAC 400.1 FVZ and then lastly left on a continuous rotating mixerovernight for 16 h to achieve suitable dispersion of the carbon black.The samples were then centrifuged at 4000 rpm for 4 h to aid in thesedimentation of the carbon black and then the supernatant was carefullydecanted into an empty vial for analysis to be analyzed by UV-VIS. Theadsorption appearing at 286 nm, presumed to be due to the aromatic ringassociated with the quenching moiety, was used to quantify the remainingdispersant concentration in the supernatant after contact with thecarbon black.

Thermogravimetric analysis (TGA) experiments were performed on a Q50 (TAInstrument) thermogravimetric analyzer. The furnace atmosphere wasdefined by 10 mL-min-nitrogen. Samples were prepared by loading aplatinum sample pan with 10-20 mg of material. The samples weresubjected to a temperature ramp of 10° C. min⁻¹ from 10° C. to 600° C.The onset and midpoint degradation temperature were determined from the5 wt % and 50 wt % loss temperatures after plateau from residual solventloss, respectively.

Evaluation of the corrosiveness of base oil with PIB-PzEA-Phthalimidewas conducted according to the method described in ASTM D6594-14entitled “Standard Test Method for Evaluation of Corrosiveness of DieselEngine Oil at 135° C.,” which is hereby incorporated herein by referencein its entirety. Briefly, metal specimens (lead or copper) were placedin base oil containing 6 wt % PIB-PzEA-Phthalimide and heated at 135° C.for 168 h. Trace metal analysis of the oil was the conducted usinginductively coupled plasma atomic emission spectroscopy (ICP-AES).Further corrosion testing was performed with a copper strip test wasaccording to ASTM D130. Here, copper strips were heated in oilcontaining 6 wt % PIB-PzEA-Phthalimide at 100° C. for 3 h. At the end ofthe heating period, the copper strip was removed, washed, and the colorand tarnish level assessed against the ASTM Copper Strip CorrosionStandard.

Fluoroelastomer compatibility testing using base oil with 6 wt %PIB-PzEA-Phthalimide was conducted using the DC-AK6 seal compatibilitytesting method. Here, elastomer samples were immersed in 270 g of baseoil and heated at 150° C. for 168 h after which the sample was testedfor volume variation, hardness variation, elongation at break, andtensile strength at break. Changes in properties were compared to thatof reference elastomer samples.

EXAMPLES Example 1: Synthesis of Primary Bromide-Terminated PIB (PIB-Br)

A primary bromide-terminated PIB homopolymer was synthesized underreversible deactivation-type living carbocation polymerizationconditions using methodologies know in the art. This example involved insitu alkylation of (3-bromopropoxy)benzene by living polyisobutylenefrom a monofunctional initiator. Briefly, the polymerization/alkylationwas performed within a N₂-atmosphere dry box equipped with a cryostatbath. To a 60/40 (v/v) mixture of hexane (655 mL)/methyl chloride (438mL) at −60° C. were added 2,6-lutidine (0.53 mL, 0.49 g),2-chloro-2,4,4-trimethylpentane (22.319 g), and isobutylene (374 mL, 257g). The polymerization of isobutylene was catalyzed by the addition ofTiCl₄ (4.15 mL, 7.18 g). The polymerization was complete inapproximately 2.5 h, at which point (3-bromopropoxy)benzene (60.00 mL)was added, followed immediately by 28.77 mL (49.77 g) of TiCl₄. Thequenching reaction was allowed to proceed overnight. Quantitativecapping of the chain ends by (3-bromopropoxy)benzene was confirmed by ¹HNMR. The catalyst was destroyed by the addition of excess methanol, andthe polymer was recovered after volatilization of the methyl chlorideand precipitation from hexane into methanol. FIG. 1A shows the ¹H-NMRfor the product. The number average molecular weight of the finalpolymer was 1.95×10³ g/mol with a polydispersity of 1.12.

Example 2: Protection of 1-(2-aminoethyl)piperazine

The primary amine of 1-(2-aminoethyl)piperazine was protected by forminga Schiff base with methyl isobutyl ketone. Briefly,1-(2-aminoethyl)piperazine (26.5 mL, 26.1 g) and methyl isobutyl ketone(900 mL) were charged into a 2 L, three-neck, round-bottom flaskequipped with magnetic stirrer, heating mantle, reflux condenser andDean-Stark trap, septa, and nitrogen inlet and outlet. The resultingsolution was heated to reflux under continuous N₂ purge. After 4 h,quantitative removal of the water by-product (3.65 mL) was observedindicating quantitative formation of the Schiff base.

Example 3: Reaction of PIB-Br with Protected 1-(2-aminoethyl)piperazine

Once the formation of the Schiff base above was complete, solid K₂CO₃(14.96 g) and a solution prepared from 60.20 g of PIB-Br and methylisobutyl ketone (100 mL) was added to the reaction vessel. The solutionwas allowed to reflux for 4 h, at which point quantitative reaction wasobserved with the use of ¹H NMR by monitoring the shift of the methyleneprotons on the (3-bromopropoxy)benzene moiety from 4.08 to 3.98 ppm.

Example 4: Preparation of Polyisobutylene-Piperazinylethylamine(PIB-PzEA)

Residual methyl isobutyl ketone was removed from the reaction aboveunder reduced pressure and replaced with a 2:1 mixture oftetrahydrofuran (500 mL) and water (250 mL). The solution was heated at50° C. overnight to allow for quantitative hydrolysis of the Schiff baseand release of methyl isobutyl ketone protecting group. Completedeprotection was confirmed through ¹H NMR by observing the disappearanceof characteristic peaks associated with the Schiff base. The resultingpolyisobutylene-piperazinylethylamine (PIB-PzEA) was separated fromresidual 1-(2-aminoethyl)piperazine by precipitation from hexane intomethanol. The structure was confirmed by NMR analysis, as shown in FIGS.1B, 2, and 3.

Example 5: Synthesis of PIB-PzEA-Phthalimide

PIB-PzEA (43.02 g) was charged to a reaction vessel equipped with amechanical stirrer and dry nitrogen gas inlet and outlet. The neatPIB-PzEA was warmed to 65° C. under N₂ to reduce its viscosity. Stirringwas activated, and 1.5 eq of solid phthalic anhydride (4.55 g) was addedto the flask. The temperature was increased to 160° C., and theinitially inhomogeneous mixture became homogeneous. The reaction wascontinued at 160° C. for 1.5 h. Reaction and ring-closure to form theimide was confirmed using ¹H NMR by observing the appearance of peaks at7.82 and 7.73 ppm associated with the phenyl protons of the phthalimidegroup along with the shift of the penultimate methylene protons closestto the imide nitrogen from 2.79 to 3.78 ppm. See FIG. 4. The resultingPIB-PzEA-Phthalimide was separated from excess phthalic anhydride byprecipitation from hexane into acetone. The product analytical resultsare as follows: nitrogen=1.56 wt %; total base number=20.2 mg KOH/g(ASTM D2896) and 9.9 mg KOH/g (ASTM D4739).

Example 6: Synthesis of PIB-PzEA-Naphthalimide

A scintillation vial equipped with a N₂ purge and a magnetic stir barwas charged with PIB-PzEA (1.142 g) and 1.15 eq of 1,8-naphthalicanhydride (0.120 g). The neat polymer was warmed to 65° C. under N₂ toreduce its viscosity and facilitate magnetic stirring. The vial contentswere heated to 160° C. with stirring for 2.5 hours upon which themixture was observed to bubble, indicating evolution of the waterby-product. Reaction and ring-closure of the imide was confirmed using¹H NMR by observing the appearance of peaks at 8.60, 8.21, and 7.73 ppmassociated with the phenyl protons of the naphthalimide group along withthe shift of the penultimate methylene protons closest to the imidenitrogen from 2.79 to 4.36 ppm.

See FIG. 4. The resulting polymer was then separated from excessnaphthalic anhydride by precipitation from hexane into acetone.

Example 7: Synthesis of PIB-PzEA-Glutarimide

A 10 mL roundbottom flask was charged with a magnetic stirrer, 1.152 g(0.55 mmol) of PIB-PzEA, and 0.120 g (0.89 mmol) of glutaric anhydride.The flask was stoppered with a strong N₂ purge and the reaction washeated to 160° C. for 2 hours. Upon cooling to room temperature, thePIB-PzEA-Glutarimide was collected and purified by dissolution intohexane, precipitation into anhydrous acetone, and vacuum stripping at40° C. The structure was confirmed by NMR analysis, as shown in FIG. 4.

Example 8: Synthesis of PIB-PzEA-Maleimide

Maleic anhydride (0.053 g) and tetrahydrofuran (15 mL) were charged intoa 50 mL, 2-neck, round-bottom flask equipped with magnetic stirrer,heating mantle, reflux condenser and Dean-Stark trap, septa, andnitrogen inlet and outlet. The resulting solution was cooled to 0° C.Next, 0.85 eq of PIB-PzEA (1.006 g) dissolved in tetrahydrofuran (5 mL)was added dropwise, and the solution was stirred for an additional 30min. The solution was then allowed to warm to room temperature andsubsequently heated to reflux for 2 h. Tetrahydrofuran was thendistilled from the flask under vacuum and replaced with dodecane (10mL). The resulting solution was heated at 160° C. under N₂ for 1.5 h,and the water of imidization was separated using a Dean-Stark apparatus.Reaction and ring-closure of the imide was confirmed using ¹H NMR byobserving the appearance of a peak at 6.69 ppm associated with theolefinic protons of the maleimide moiety along with the shift of thepenultimate methylene protons closest to the imide nitrogen from 2.79 to3.65 ppm. The resulting PIB-PzEA-Maleimide was then separated fromexcess maleic anhydride by precipitation from hexane into acetone.

Example 9: Synthesis of PIB-PzEA-Pyromellitimide

Into a 50 mL, 3-neck, round-bottom flask equipped with magnetic stirrer,heating mantle, reflux condenser and Dean-Stark trap, septa, andnitrogen inlet and outlet were charged PIB-PzEA (2.956 g) andtetrahydrofuran (25 mL). To the resulting solution was added 0.5 eq ofpyromellitic dianhydride (0.146 g). The mixture was refluxed for 4 hunder N₂ to form the amic-acid derivative. Tetrahydrofuran was thendistilled from the flask under vacuum and replaced with dodecane (25mL). The resulting solution was heated at 160° C. under N₂ for 2 h, andthe water of imidization was separated using the Dean-Stark apparatus.Reaction and ring-closure of the imide was confirmed using ¹H NMR byobserving the appearance of a peak at 8.23 ppm associated with thearomatic protons of the pyromellitimide moiety along with the shift ofthe penultimate methylene protons closest to the imide nitrogen from2.79 to 3.84 ppm. See FIG. 5. The resulting polymer was then collectedby precipitation from hexane into acetone. The number average molecularweight of the final polymer was 4.59×10³ g/mol with a polydispersity of1.10. See FIG. 6.

Example 10: Synthesis of Poly(styrene-alt-(PIB-PzEA-Maleimide))

PIB-PzEA (2.956 g) and tetrahydrofuran (25 mL) were charged into a 50mL, 2-neck, round-bottom flask equipped with magnetic stirrer, heatingmantle, reflux condenser and Dean-Stark trap, septa, and nitrogen inletand outlet. To the resulting solution was added apoly(styrene-alt-maleic anhydride) copolymer (0.11 g) having a molecularweight of 1,600 g/mol and an acid number of 495 mg KOH/g (Sigma AldrichCo.). The solution was refluxed for 4 h under N₂ to form the amic-acidderivative. Tetrahydrofuran was then distilled from the flask undervacuum and replaced with dodecane (10 mL). The resulting solution washeated at 160° C. under N₂ for 2 h, and the water of imidization wasseparated using the Dean-Stark apparatus. The resultingpoly(styrene-alt-(PIB-PzEA-maleimide)) was then collected byprecipitation from hexane into acetone. Reaction and ring-closure of theimide was confirmed using ¹H NMR by observing the appearance of a broadpeak assigned to the penultimate methylene protons closest to the imidenitrogen, centered at 3.40 ppm. The number average molecular weight ofthe poly(styrene-alt-(PIB-PzEA-maleimide)) was 5.33×10⁴ g/mol with apolydispersity of 1.32.

Example 11: Protection of Diethylenetriamine (DETA)

The primary amine of diethylenetriamine (DETA) was protected by forminga Schiff base with methyl isobutyl ketone. Briefly, diethylenetriamine(3.94 mL, 3.76 g) and methyl isobutyl ketone (50 mL) were charged into a2 L, three-neck, round-bottom flask equipped with magnetic stirrer,heating mantle, reflux condenser and Dean-Stark trap, septa, andnitrogen inlet and outlet. The resulting solution was heated to refluxunder continuous N₂ purge. After 4 h, quantitative removal of the waterby-product (1.31 mL) was observed indicating quantitative formation ofthe Schiff base.

Example 12: Reaction of PIB-Br with Protected DETA

Once the formation of the Schiff base above was complete, solid K₂CO₃(7.48 g) and a solution prepared from 7.074 g of PIB-Br and methylisobutyl ketone (10 mL) was added to the reaction vessel. The solutionwas allowed to reflux for 4 h, at which point quantitative reaction wasobserved with the use of ¹H NMR by monitoring the shift of the methyleneprotons on the (3-bromopropoxy)benzene moiety from 4.08 to 3.99 ppm.

Example 13: Preparation of Polyisobutylene-Diethylenetriamine (PIB-DETA)

Residual methyl isobutyl ketone was separated from the polymer byprecipitation into acetone. Upon recovery, the polymer was solubilizedin a 2:1 mixture of tetrahydrofuran (100 mL) and water (50 mL). Thesolution was heated at 50° C. overnight to allow for quantitativehydrolysis of the Schiff base and release of methyl isobutyl ketoneprotecting group. Complete deprotection was confirmed through ¹H NMR byobserving the disappearance of characteristic peaks associated with theSchiff base. The resulting polyisobutylene-diethylenetriamine (PIB-DETA)was separated by precipitation from hexane into acetone.

Example 14: Synthesis of PIB-DETA-Phthalimide

PIB-DETA (0.714 g) and 10 mL THF were charged into a 25 mL, three-neck,round-bottom flask equipped with magnetic stirrer, heating mantle,reflux condenser and Dean-Stark trap, septa, and nitrogen inlet andoutlet. Stirring was activated, and 3.95 eq of solid phthalic anhydride(0.199 g) was added to the flask. The mixture was refluxed for 4 h underN₂ to form the amic-acid derivative. Tetrahydrofuran was then distilledfrom the flask under vacuum. The resulting polymer was heated at 160° C.under N₂ for 2 h, and the water of imidization was separated using theDean-Stark apparatus. Reaction and ring-closure to form the imide wasconfirmed using ¹H NMR by observing the appearance of peaks at 7.73 and7.65 ppm associated with the phenyl protons of the phthalimide group.The resulting PIB-DETA-Phthalimide was separated from excess phthalicanhydride by precipitation from hexane into acetone. The structure wasconfirmed by NMR analysis, as shown in FIG. 7.

Synthetic Methodology

As depicted in Scheme 1, a facile and modular synthetic route wasdeveloped to access PIB-PzEA and PIB-PzEA-derived dispersants. By way ofexample, Scheme 1 illustrates the synthesis ofpolyisobutylene-piperazinylethylamine (PIB-PzEA) followed by subsequentimidization with 1,8-naphthalic anhydride to affordPIB-PzEA-naphthalimide. It is understood that alternative polyolefindispersants can be prepared simply by varying the polyolefin, quenchingagent, polyamine, and anhydrides employed in the modular synthesis.

Example polyamines of interest include 1-(2-aminoethyl)piperazine anddiethylenetriamine, which can provide mono- and di-functionaldispersants in terms of the number of polar head groups, respectively.Other suitable polyamines include, for example,N-methyl-1,3-diaminopropane,4-[2-(1-piperazinyl)ethyl]-1-piperazineethanamine, triethylenetetramine(TETA), triethylenepentamine (TEPA), pentaethylenehexamine (PEHA),hexaethyleneheptamine (HEHA), N-phenyl-p-phenylenediamine, andN-benzylethylenediamine. Example anhydrides of interest include, forexample, maleic anhydride, phthalic anhydride, and glutaric anhydride.Other suitable anhydrides include, for example, dianhydrides (e.g.,pyromellitic dianhydride or naphthalenetetracarboxylic dianhydride) aswell as other polycyclic anhydrides (e.g., poly(styrene-alt-maleicanhydride)).

Preparation of Dispersants

Example dispersants, polyisobutylene-piperazinylethylamine-glutarimide(PIB-PzEA-Glutarimide), polyisobutylene-piperazinylethylamine-phthalimide (PIB-PzEA-Phthalimide), andpolyisobutylene-piperazinylethylamine-naphthalimide(PIB-PzEA-Naphthalimide) were prepared by reaction of PIB-PzEA withsuitable anhydrides. The dispersants include one or more tertiary aminesand at least a phenyl ring, but lack primary and secondary amines.

MALDI-TOF mass spectrometry was also used to determine end-groupfunctionality and confirm the structure of PIB-DETA and PIB-PzEA-deriveddispersants. The MALDI-TOF mass spectra of PIB-PzEA andPIB-PzEA-Phthalimide, which are representative, are shown in FIGS. 8Aand 8B, respectively. Each sample displayed a single, major distributionof polymeric species, associated with either Ag or Na cations from thecationizing agent (AgTFA or NaTFA), differing from each other only bythe number of isobutylene repeat units. As shown in FIG. 9, the datafrom each mass spectra were analyzed by linear regression of a plot ofmass-to-charge ratio (M/z, assumed to be 1), measured at the maximum ofeach peak of the major distribution, versus degree of polymerization(DP). The slope of this plot is theoretically equivalent to the exactmass of the isobutylene repeat unit, 56.06 Da. The y-intercept istheoretically equivalent to EG+I+C, where EG is the exact mass of thePzEA end group, I is the exact mass of the TMPCl initiator residue(113.22 Da), and C is the relative mass of the associated Ag (107.86 Da)or Na (22.99 Da) cation. MALDI-TOF-MS and GPC characterization data ofthe PIB-DETA and PIB-PzEA-derived dispersants is summarized in Table 1.

TABLE 1 GPC and MALDI-TOF MS Data of PIB—DETA and PIB—PzEA-DerivedDispersants M_(n) PDI M_(n) PDI EG EG Sample (GPC) (GPC) (MALDI) (MALDI)MW_(theo) MW_(expt) Diff. M_(ru) PIB—Br 1,950 1.12 1,760.05 1.02 215.09219.99 4.90 56.21 PIB—PzEA — — 1,921.71 1.02 279.15 279.11 0.04 56.14PIB—PzEA- 2,552 1.09 1,791.32 1.02 392.47 398.09 5.62 56.13 PhthalimidePIB—PzEA- 2,816 1.16 1,716.65 1.02 442.56 448.23 5.67 56.13Naphthalimide PIB—PzEA- 2,378 1.11 2,058.26 1.02 358.45 357.97 0.4856.09 Glutarimide PIB—PzEA- 4,590 1.11 3,400.98 1.03 708.89 711.35 2.4656.05 Pyromellitimide PIB—DETA — — 1,695.85 1.03 236.53 242.39 5.8656.16 PIB—DETA- — — 2,440.06 1.01 496.53 494.25 2.28 56.12 Phthalimide

PIB-PzEA and PIB-DETA-derived dispersants were tested for thermalstability by thermogravimetric analysis. See FIG. 10. All dispersantsexhibited similar decomposition behavior regardless of end-groupstructure. Loss of residual hexane is observed at low temperatures uponwhich a steady plateau is reached. Rapid decomposition occurred once theonset temperature was reached and all dispersants were completelydecomposed over a short temperature range of approximately 70° C. Theend-group structures of the dispersants comprise 20 wt % or less of themolecular weight and as such, the degradation temperature, and rate ofdecomposition will be relatively unaffected regardless of the identityof the end-group structure, as summarized in Table 2.

TABLE 2 TGA Data of PIB-DETA and PIB-PzEA-Derived Dispersants T_(d)(onset)^(a) T_(d) (midpoint)^(b) Sample (° C.) (° C.) PIB-PzEA 373.29412.82 PIB-PzEA-Pyromellitimide 389.38 416.34 PIB-PzEA-Glutarimide379.68 414.63 PIB-PzEA-Phthalimide 382.95 413.26 PIB-PzEA-Naphthalimide380.87 416.04 PIB-DETA 350.47 413.45 PIB-DETA-Phthalimide 355.85 410.24Poly(styrene-alt-(PIB-PzEA-Maleimide)) 380.14 416.20 ^(a)5% weight lossafter residual hexane removal, ^(b)50% weight loss after residual hexaneremoval.

Following industry protocols (ASTM D-6594-14, entitled “Standard TestMethod for Evaluation of Corrosiveness of Diesel Engine Oil at 135° C.,”which is hereby incorporated herein by reference), PIB-PzEA-Phthalimidewas tested for its corrosiveness of copper and lead metal. Oilcontaining PIB-PzEA-Phthalimide showed limited corrosion of copper andlead metal. As detailed in Table 3, the corrosiveness of the lubricatingoil containing PIB-PzEA-Phthalimide was within passing standards forboth copper and lead corrosion.

TABLE 3 High Temperature Corrosion Test of Oil with PIB-PzEA-PhthalimideOil Test with PIB-PzEA-Phthalimide^(a) Change in ConcentrationAcceptable Limits Metal Type (ppm) (ppm) Copper (Cu) 4.0 <20.0 Lead (Pb)35.0 <120.0 ^(a)Conducted at 6 wt % PIB-PzEA-Phthlimide

Compatibility of PIB-PzEA-Phthalimide with fluroelastomers was evaluatedusing the compatibility tests described in ASTM D7216-15 (entitled“Standard Test Method for Determining Automotive Engine OilCompatibility with Typical Seal Elastomers,” which is herebyincorporated herein by reference) using DC-AK6 type elastomer. The testresults are summarized in Table 4. Minimal changes in mechanicalproperties were observed and all tests were within passing parameters.

TABLE 4 Mechanical Properties of AK6 Fluoroelastomer After Exposure toPIB-PzEA-Phthalimide Oil Test with PIB- Acceptable Testing MethodPzEA-Phthalimide^(a,b) Limits Volume Variation (%) 0.78 −1/+5 HardnessVariation (Points) −1 −1/+5 Tensile Strength Variation (%) −32.4 −50/+10Elongation at Break Variation (%) −36.2 −60/+10 ^(a)Conducted at 6 wt %PIB-PzEA-Phthalimide, ^(b)Test results were an average of threemeasurements

The affinity for adsorption of PIB-PzEA-Glutarimide,PIB-PzEA-Phthalimide, PIB-PzEA-Naphthalimide, andPIB-PzEA-Pyromellitimide onto Vulcan XC-72R carbon black was studiedusing UV-VIS supernatant depletion assay. Construction of individualcalibration curves and subsequent studies were based off UV absorbancesobserved for PIB-PzEA-Glutarimide (285 nm), PIB-PzEA-Phthalimide (285nm), PIB-PzEA-Naphthalimide (286 nm) and PIB-PzEA-Pyromellitimide (285nm) attributed to the aromatic chromophore present in the phenoxyquencher. With the collected data from UV-VIS supernatant depletionassay, Langmuir isotherms were generated and then linearized in the formof two separate equations,

$\begin{matrix}{{\frac{C_{e}}{q_{e}} = {\frac{C_{e}}{q_{m}} + \frac{1}{q_{m}K_{a}}}},{and},} & {{Eq}.\mspace{14mu} 1} \\{{\frac{1}{q_{e}} = {{\left( \frac{1}{q_{m}K_{a}} \right)\frac{1}{C_{e}}} + \frac{1}{q_{m}}}},} & {{Eq}.\mspace{14mu} 2}\end{matrix}$in where K_(a) is the adsorption equilibrium constant, q_(m) is theequilibrium concentration of the dispersant for complete monolayercoverage of the carbon black, C_(e) is the equilibrium concertation ofthe dispersant remaining in solution after exposure to carbon black, andq_(e) which represents the adsorbed amount of dispersant onto the carbonblack at a given equilibrium concentration. The derived parameters fromthe separate linearized Langmuir isotherms are detailed in Table 5.Representation of the resulting Langmuir isotherms are shown in FIGS.11-12.

TABLE 5 Comparison of thermodynamic parameters as determined by Equation3 and 4 for PIB—PzEA-derived dispersants Langmuir (Eq. 1) Langmuir (Eq.2) q_(m) q_(m) K_(a) × 10³ K_(a) q_(m) q_(m) K_(a) × 10³ K_(a) Sample r²(mg · m⁻²) (μmol · m⁻²) (L · mg⁻¹) (m³ · mol⁻¹) r² (mg · m⁻²) (μmol ·m⁻²) (L · mg⁻¹) (m³ · mol⁻¹) Naphthalimide 0.993 0.602 0.214 1.058 2.9780.974 0.567 0.201 1.743 4.907 Phthalimide 0.978 0.470 0.184 0.205 0.5230.996 0.449 0.175 0.225 0.574 Glutarimide 0.985 0.436 0.180 0.206 0.4990.989 0.401 0.165 0.249 0.604 Pyromellitimide 0.993 0.196 0.043 5.63725.87 0.957 0.193 0.042 6.698 30.75

The compositions and methods of the appended claims are not limited inscope by the specific compositions and methods described herein, whichare intended as illustrations of a few aspects of the claims. Anycompositions and methods that are functionally equivalent are intendedto fall within the scope of the claims. Various modifications of thecompositions and methods in addition to those shown and described hereinare intended to fall within the scope of the appended claims. Further,while only certain representative compositions and method stepsdisclosed herein are specifically described, other combinations of thecompositions and method steps also are intended to fall within the scopeof the appended claims, even if not specifically recited. Thus, acombination of steps, elements, components, or constituents may beexplicitly mentioned herein or less, however, other combinations ofsteps, elements, components, and constituents are included, even thoughnot explicitly stated.

The term “comprising” and variations thereof as used herein are usedsynonymously with the term “including” and variations thereof and areopen, non-limiting terms. Although the terms “comprising” and“including” have been used herein to describe various embodiments, theterms “consisting essentially of” and “consisting of” can be used inplace of “comprising” and “including” to provide for more specificembodiments of the invention and are also disclosed. Other than wherenoted, all numbers expressing geometries, dimensions, and so forth usedin the specification and claims are to be understood at the very least,and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, to be construed in light of thenumber of significant digits and ordinary rounding approaches. Unlessdefined otherwise, all technical and scientific terms used herein havethe same meanings as commonly understood by one of skill in the art towhich the disclosed invention belongs. Publications cited herein and thematerials for which they are cited are specifically incorporated byreference.

What is claimed is:
 1. A polyolefin dispersant defined by Formula Ibelow

wherein R^(x) is an initiator residue; R^(a) is a polyolefin group; R¹and R² are each, independently in each —(CR¹R²) unit, H, alkyl, alkoxy,or alkylaryl; R³ and R⁴ are each, independently, H, alkyl, or alkoxy; mis an integer from 1 to 20; n is an integer from 1 to 6; r is an integerfrom 1 to 4; Y is a polyvalent amine linker comprising one or moretertiary amines, wherein the polyvalent amine linker does not include aprimary amine or a secondary amine; and A is absent, or comprises adispersive moiety.
 2. The dispersant of claim 1, wherein A is present.3. The dispersant of claim 2, wherein A comprises an imide moiety. 4.The dispersant of claim 3, wherein the imide moiety comprises a cyclicimide.
 5. The dispersant of claim 4, wherein the imide moiety comprisesa moiety defined by Formula III below

wherein R⁵, R⁶, and R⁷ are each, independently, H, halogen, alkyl,alkoxy, aryl, alkylaryl, or cycloalkyl, or wherein R⁵ and R⁶, togetherwith the atoms to which they are attached, R⁶ and R⁷, together with theatoms to which they are attached, or both R⁵ and R⁶ and R⁶ and R⁷,together with the atoms to which they are attached, form a 5-8 memberedsubstituted or unsubstituted aromatic or non-aromatic ring.
 6. Thedispersant of claim 5, wherein the imide moiety comprises one of thefollowing


7. The dispersant of claim 1, wherein R^(a) comprises a polyisobutylenegroup.
 8. The dispersant of claim 1, wherein Y comprises from one tothree tertiary amines.
 9. The dispersant of claim 1, wherein Y comprisesfrom 6 to 30 carbon atoms.
 10. The dispersant of claim 1, wherein R¹ andR² are each, independently H or alkyl.
 11. The dispersant of claim 1,wherein R³ and R⁴ are both H.
 12. The dispersant of claim 1, wherein Ycomprises a bivalent amine linker and n is
 1. 13. The dispersant ofclaim 12, wherein Y is defined by the structure below

wherein R⁷ and R⁸ are each, independently in each —(CR¹R²) unit, H,alkyl, alkoxy, or alkylaryl; and b is an integer from 1 to 20.